1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
#define pb push_back
#define mp make_pair
#define fi first
#define se second 
#define all(...) begin(__VA_ARGS__) , end(__VA_ARGS__)
#define boost {ios_base::sync_with_stdio(false); cin.tie(); cout.tie();}

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef vector <int> vi;
typedef pair<int,int> PII;
typedef pair<ll,ll> PLL;
constexpr ll nax = 1e6+6969, INF = 2e9+6969;

int n,m,cnt[4][nax];

int main()
{
	scanf("%d%d", &n, &m);
	for(int i=0;i<m;++i)
	{
		int a,b,c;
		scanf("%d%d%d", &a, &b, &c);
		cnt[c][a]++;
		cnt[c][b+1]--;
	}
	for(int i=1;i<=3;++i) for(int j=1;j<=n;++j) cnt[i][j] += cnt[i][j-1];
	int ans = 0;
	for(int i=1;i<=n;++i)
	{
		if(cnt[1][i] > 0 && cnt[2][i] > 0 && cnt[3][i] == 0) ans++;
	}
	printf("%d\n", ans);
	return 0;
}